Buggy code:
public Set < String > defaultIncludes ( ) { } public Map < String , String > typeMapping ( ) { } public Map < String , String > instantiationTypes ( ) { } public Set < String > reservedWords ( ) { } public Set < String > languageSpecificPrimitives ( ) { } public Map < String , String > importMapping ( ) { } public String modelPackage ( ) { } public String apiPackage ( ) { } public String fileSuffix ( ) { } public String templateDir ( ) { } public String embeddedTemplateDir ( ) { } public Map < String , String > apiTemplateFiles ( ) { } public Map < String , String > modelTemplateFiles ( ) { } public String apiFileFolder ( ) { } public String modelFileFolder ( ) { } public Map < String , Object > additionalProperties ( ) { } public List < SupportingFile > supportingFiles ( ) { } public String outputFolder ( ) { } public void setOutputDir ( String dir ) { } public String getOutputDir ( ) { } public void setTemplateDir ( String templateDir ) { } public void setModelPackage ( String modelPackage ) { } public void setApiPackage ( String apiPackage ) { } public void setSortParamsByRequiredFlag ( Boolean sortParamsByRequiredFlag ) { } public void setEnsureUniqueParams ( Boolean ensureUniqueParams ) { } public String toApiFilename ( String name ) { } public String toApiVarName ( String name ) { } public String toModelFilename ( String name ) { } public String toOperationId ( String operationId ) { } public String toVarName ( String name ) { } public String toParamName ( String name ) { } public String toEnumName ( CodegenProperty property ) { } public String escapeReservedWord ( String name ) { } public String toModelImport ( String name ) { } public String toApiImport ( String name ) { } public DefaultCodegen ( ) { } public String generateExamplePath ( String path , Operation operation ) { } public String toInstantiationType ( Property p ) { } public String toDefaultValue ( Property p ) { } public String toDefaultValueWithParam ( String name , Property p ) { } public String getSwaggerType ( Property p ) { } public String snakeCase ( String name ) { } public String initialCaps ( String name ) { } public String getTypeDeclaration ( String name ) { } public String getTypeDeclaration ( Property p ) { } public String toApiName ( String name ) { } public String toModelName ( String name ) { } public CodegenModel fromModel ( String name , Model model ) { } public CodegenModel fromModel ( String name , Model model , Map < String , Model > allDefinitions ) { } public String getterAndSetterCapitalize ( String name ) { } public CodegenProperty fromProperty ( String name , Property p ) { } protected void setNonArrayMapProperty ( CodegenProperty property , String type ) { } private Response findMethodResponse ( Map < String , Response > responses ) { } public CodegenOperation fromOperation ( String path , String httpMethod , Operation operation , Map < String , Model > definitions ) { } public CodegenOperation fromOperation ( String path , String httpMethod , Operation operation , Map < String , Model > definitions , Swagger swagger ) { } public CodegenResponse fromResponse ( String responseCode , Response response ) { } public CodegenParameter fromParameter ( Parameter param , Set < String > imports ) { } public List < CodegenSecurity > fromSecurity ( Map < String , SecuritySchemeDefinition > schemes ) { if ( schemes == null ) { <START_BUG> return null ; <END_BUG> } List < CodegenSecurity > secs = new ArrayList < CodegenSecurity > ( schemes . size ( ) ) ; for ( Iterator < Map . Entry < String , SecuritySchemeDefinition > > it = schemes . entrySet ( ) . iterator ( ) ; it . hasNext ( ) ; ) { final Map . Entry < String , SecuritySchemeDefinition > entry = it . next ( ) ; final SecuritySchemeDefinition schemeDefinition = entry . getValue ( ) ; CodegenSecurity sec = CodegenModelFactory . newInstance ( SECURITY ) ; sec . name = entry . getKey ( ) ; sec . type = schemeDefinition . getType ( ) ; if ( schemeDefinition instanceof ApiKeyAuthDefinition ) { final ApiKeyAuthDefinition apiKeyDefinition = ( ( ApiKeyAuthDefinition ) ( schemeDefinition ) ) ; sec . isBasic = sec . isOAuth = false ; sec . isApiKey = true ; sec . keyParamName = apiKeyDefinition . getName ( ) ; sec . isKeyInHeader = ( apiKeyDefinition . getIn ( ) ) == ( In . HEADER ) ; sec . isKeyInQuery = ! ( sec . isKeyInHeader ) ; } else if ( schemeDefinition instanceof BasicAuthDefinition ) { sec . isKeyInHeader = sec . isKeyInQuery = sec . isApiKey = sec . isOAuth = false ; sec . isBasic = true ; } else { final OAuth2Definition oauth2Definition = ( ( OAuth2Definition ) ( schemeDefinition ) ) ; sec . isKeyInHeader = sec . isKeyInQuery = sec . isApiKey = sec . isBasic = false ; sec . isOAuth = true ; sec . flow = oauth2Definition . getFlow ( ) ; sec . authorizationUrl = oauth2Definition . getAuthorizationUrl ( ) ; sec . tokenUrl = oauth2Definition . getTokenUrl ( ) ; if ( ( oauth2Definition . getScopes ( ) ) != null ) { List < Map < String , Object > > scopes = new ArrayList < Map < String , Object > > ( ) ; int count = 0 ; int numScopes = oauth2Definition . getScopes ( ) . size ( ) ; for ( Map . Entry < String , String > scopeEntry : oauth2Definition . getScopes ( ) . entrySet ( ) ) { Map < String , Object > scope = new HashMap < String , Object > ( ) ;

Fix:
return Collections . emptyList ( ) ;